Fadnavis said the poll outcome in the southern state was a "mandate of faith" in the prime minister and the credit for it should go to the election strategy of BJP president Amit Shah.

"My congratulations to B S Yeddyurappa and the people of Karnataka. This has set the course for a bigger victory of the BJP and the NDA in the 2019 Lok Sabha polls," he added.

According to Election Commission (EC) figures at 4 pm, the BJP had won 78 seats and was leading in 26 Assembly segments in Karnataka, well on course to emerge as the single largest party in the southern state.

The ruling Congress had won 49 seats and was leading in 29 constituencies.

Like all the state polls since he assumed power in New Delhi, Prime Minister Modi had helmed the BJP's adrenaline-charged campaign in Karnataka, despite the party having declared B S Yeddyurappa its chief ministerial candidate, while Congress president Rahul Gandhi had spearheaded the campaign of his party.

Modi had launched a blitzkrieg on May 1, addressing a number of rallies, in his bid to wrest the key southern state, which Shah had dubbed as the party's "gateway to the south", from the Congress.

The prime minister had addressed at least three rallies every day when he was in Karnataka, or else, interacted with the workers of the BJP's different frontal organisations through the "Namo" app.

Though development was a part of the political discourse, it was overtaken by a slanging match between the two parties over corruption.